rectangulus

Forms

rēctangulus (feminine rēctangula, neuter rēctangulum); first/second-declension adjective^[1] Late Latin rēctiangulus.^[2][3]

Etymology

It is formed from Latin rēctus (“straight, right”) + angulus (“angle”),^[2][3][1] and corresponds to Ancient Greek ὀρθογώνιος (orthogṓnios).^[2] Late Latin writers spell it ⟨rēctiangulus⟩;^[2][3] medieval writers in Britain use both spellings.^[4]

Earliest recorded meaning

It first appears, as rēctiangulus, in Boethius' writings on division and on geometry, of triangles and quadrilaterals with right angles.^[2][3]

Semantic evolution

Isidore of Seville uses the neuter rēctiangulum as a noun for a right-angled triangle.^[3][5] The Latin Euclid distinguishes the square, which is equilateral and right-angled, from the oblong, which is right-angled but not equilateral.^[2]

Medieval geometry kept it: Adelard of Bath's version of Euclid calls a square figure right-angled, and Robert of Chester speaks of a right-angled parallelogram.^[4] The neuter noun rēctangulum meant a right angle in Late Latin and a rectangle in Medieval Latin.^[1]

Timeline

• c. 560–636 AD – Isidore of Seville uses the noun rēctiangulum for a right-angled triangle.^[3][5][6]
• 1326 – The spelling rēctangulus is recorded in British medieval Latin.^[6]

Meanings

Adjective

1. right-angled, rectangular.^[2][3][4][1]
2. (of a triangle) Having a right angle.^[4][2]

Usage notes

As a noun, the neuter rēctiangulum is a right-angled triangle in Isidore,^[3][5] and rēctangulum is a right angle in Late Latin and a rectangle in Medieval Latin.^[1]

References

1. ^ a b c d e f g Wiktionary, the free dictionary, https://en.wiktionary.org
2. ^ a b c d e f g h Thesaurus linguae Latinae (1900–), Leipzig: Teubner; Berlin: De Gruyter; open-access ed., Munich: Bayerische Akademie der Wissenschaften
3. ^ a b c d e f g h Georges, Karl Ernst (1913–1918), Ausführliches lateinisch-deutsches Handwörterbuch, 8th ed., ed. Heinrich Georges, Hannover; Leipzig: Hahn
4. ^ a b c d Latham, R. E., D. R. Howlett, R. K. Ashdowne, et al. (1975–2013), Dictionary of Medieval Latin from British Sources, London: British Academy / Oxford University Press
5. ^ a b c Conte, Gian Biagio; Pianezzola, Emilio; Ranucci, Giuliano (2010), il Latino: Vocabolario della lingua latina, 3rd ed., Florence: Le Monnier
6. ^ a b Köbler, Gerhard (2010), Lateinisches Abkunfts- und Wirkungswörterbuch für Altertum und Mittelalter, online ed., koeblergerhard.de